1. Field of the Invention
The invention relates to a contact protection housing for at least one electrical terminal that is disposed in a housing part which is mounted on a component and in which an opening for introducing potting composition is made. The invention also relates to an injection pump, having a contact protection housing as described above. The invention also relates to a method for mounting a contact protection housing, with an adapter.
2. Description of the Prior Art
German Patent Disclosure DE 197 03 686 discloses a contact protection housing which comprises two assembled housing parts. There is a seal between the two housing parts. The seal holds back potting composition that has not yet set during filling. The seal must be positioned precisely when the contact protection housing is put together. Furthermore, the seal is vulnerable to wear.
It is an object of the invention to furnish a contact protection housing which is formed of fewer individual parts than conventional contact protection housings. The effort and expense of assembly should also be reduced.
In a contact protection housing for at least one electrical terminal that is disposed in a housing part which is mounted on a component and in which an opening for introducing potting composition is made, this object is attained in that the housing part is formed by a thin-walled cap, whose edge rests constantly on the component by initial tension. This offers the advantage that the seal required in conventional contact protection housings can be omitted.
A particular embodiment of the contact protection housing of the invention is characterized in that the cap takes the form of a cylinder, open on one face end, on whose jacket face a protrusion tapering to a sharp point is provided, the flanks of which protrusion are embodied as slightly concave. The concave embodiment brings about an elastic adaptation of the flanks of the cap to the component. As a result, production-dictated tolerances of the component can be compensated for. Venting the cavity during the potting takes place automatically via the remaining slight gaps between the line holder and a magnet valve with which it is used.
In an injection pump, in particular a distributor injection pump, for motor vehicles, on which pump a magnet valve is secured with the aid of a hollow clamping screw, the above-stated objected is attained by a contact protection housing whose protrusion protrudes past the circumference or inside diameter of the hollow clamping screw. As a result, in the mounted state, an undesired dismantling of the magnet valve is reliably prevented.
In the use of the cap of the invention, quality problems in the region of the gate have occurred at high fill nozzle temperatures. It is therefore a further object of the invention to disclose a fast mounting method in which even at high fill nozzle temperatures, damage to the potting composition is averted.
In a method for mounting a contact protection housing as described above on a component, in particular on an injection pump as described above, in which the potting composition is introduced with the aid of a nozzle, this object is attained in that while the potting composition is being introduced, there is an adapter disposed between the cap and the nozzle. The adapter part separates the nozzle from the cavity. The spacing, forced by the adapter part, between the cap and the nozzle prevents thermal destruction of the potting composition in the region of the fill opening in the cap.
An adapter for the use of the method described above is characterized in that the adapter has a through bore with a first portion, whose diameter is larger than the diameter of the opening in the cap for introducing the potting composition, and having a conical second portion, which tapers from the inside outward. The first portion serves to compensate for imprecisions in attaching the nozzle to the cap. As a result, perfect filling of the cap is also assured even if the nozzle opening is not disposed precisely concentrically with the cap opening. The forming composition remaining outside the cap in the region of the cap opening after the filling operation forms a button, which is integral with the forming composition in the interior of the cap. The button has a larger diameter than the opening in the cap and as a result prevents detachment and undesired removal of the cap after mounting. The conical second portion of the adapter serves to seal off the fill nozzle and center it.
A particular type of embodiment of the adapter of the invention is characterized in that the first portion tapers from the inside outward. This assures good unmolding once the potting composition has been introduced into the cap.
A further embodiment of the adapter of the invention is characterized in that a cylindrical third portion is disposed between the first portion and the second portion. The connection can also be conical, with tapering in the direction of the nozzle, and/or can be profiled. The third portion allows the potting composition to pass through in the introduction process. Via the length of the third portion, the spacing between the nozzle and the cap can be varied. The magnitude of the spacing between the nozzle and the cap depends, among other factors, on the temperature of the nozzle in the introduction process.